When it comes to towing there are a lot of factors involved:
- What is the weight of the vehicle being towed??? Not a guess, the actual weight.
- What is the weight of the trailer or tow dolly?
- What is the weight of the tools, tires, parts, jacks, racing supplies, etc. you take with you to the track?
- Do you go to the track alone or with other people who are riding with you? Do those people bring "stuff" with them (coolers, chairs,etc)?
Toyota's published towing capacity for your 4Runner is 5,000lbs. If you have an accident while towing that is the number that the police will use during their accident investigation (since that is the only number Toyota published for the V6 4Runner). If you are over that weight you could be cited by the police for various violations. If during an accident you hurt or kill someone being overweight opens you up to being sued.
As you can see from the photo my profile, I tow my cars with my Toyota. I have been to all of the same tracks you mentioned in your post.
I am also anal about safety when it comes to towing (ie balancing my load, using a weight distributing hitch/receiver setup, dual cam sway control, towing mirrors, etc). During the 5+ years I have been towing there have been situations I have found myself in that being very safety conscious has saved my Butt.
One last suggestion, if you do start towing re-check your vehicle insurance.
Having an insurance policy with minimal coverage (especially liability) is NOT the best idea if you are going to tow. Accidents involving trailers and tow vehicles can be much more serious and costly than just a vehicle accident. Your insurance should take that into account.
Good Luck with racing and have fun. The same goes for Towing.